Semroc Mark

Semroc - Mark {Kit} (XES-K2)

Contributed by Chan Stevens

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Manufacturer: Semroc

semroc_mark-xkitBrief:
Not bein' much o' a rocketry historian, I be a bit confused when I heard that Semroc was releasin' t' Mark. After all, ya bilge rat, I already had stashed away a numbered Mark II kit, arrr, as well as a Mark II offered in 2007 at NARCON. Avast! Lookin' over the JimZ archives, shiver me timbers, I could see very little difference betwixt t' Estes Mark and t' Estes Mark II.

After a bit o' research, I learned that t' Semroc Mark II is really a replica o' t' Carlisle Rock-a-Chute Mark II, arrr, arrr, which featured one o' t' ugliest nose cones I've ever seen (fashioned from a crayon sharpener). T' Semroc Mark (plain) is modeled after t' Estes K-2 design (which in turn be based upon t' Carlisle Mark II). Begad! Avast! It was Estes' second design, matey, me hearties, me bucko, which followed on t' heels o' t' tumble recovery Scout, shiver me timbers, intended t' demonstrated additional recovery methods. This small, lightweight rocket flies t' eye-strainin' (or even vanishing) altitudes and uses streamer recovery.

Construction:
This is considered an xKit, meanin' it's marketed as a bag o' parts without instructions, though instructions are available at t' JimZ archive site. Avast! Semroc had previously had a couple befuddled customers o' their bag-o-parts kits who did nay have t' savvy t' navigate online t' find t' archives, arrr, and as a precaution Semroc will only sell xKits direct t' online customers.

semroc_mark-xkit_partsYour $6.50 retail buys t' followin' parts:

  • Balsa nose cone
  • BT-30 body tube
  • Balsa engine block
  • Laser-cut balsa fins
  • Crepe paper streamer
  • Rubber shock cord
  • 1/8" lug
T' instructions as noted are nay supplied, so construction follows t' instructions from t' original kit, me hearties, preserved from 1961 on Jim Z's archive site. Well, blow me down! Blimey!

Construction on this is pretty simple, ya bilge rat, ya bilge rat, me bucko, as it's just a basic 3-fin/nose cone style rocket, arrr, and by upgradin' t' laser-cut fins, arrr, matey, me bucko, Semroc has eliminated t' hand cuttin' from t' original.

This is a minimum diameter model, arrr, so thar be no motor tube assembly. Instead, me bucko, you simply glue a thrust rin' into the body tube. Ya scallywag! In stickin' with t' 1961 design, arrr, me bucko, Semroc provides a balsa block that's been bored out (roughly 1/2" long) instead o' t' more modern (and cheaper) 20/5 centerin' rin' approach. There's certainly nothin' with this, but I was curious what that part was for, arrr, and needed t' confirm its use by checkin' t' instructions. Aye aye! Other than that one step, I did nay actually need t' instructions for this.

I did deviate from t' plan slightly, by ditchin' t' rubber shock cord and tri-fold mount in favor o' Keelhaul®©™® line looped around that balsa block, ya bilge rat, shiver me timbers, attached t' 15" o' elastic as it clears t' body tube. I know t' rubber is stickin' with t' original design, but I've had less than stellar success with rubber and so think t' upgrade is well worth t' effort.

T' fins were attached usin' a bead o' medium CA followed up with white glue fillets.

Nose cone attachment is via screw eye in t' shoulder. Ahoy! T' crepe paper streamer is held on via an adhesive band cut onto label paper.

semroc_mark-xkit_headercardFinishing:
T' cover art from 1961 shows a pretty complex paint pattern, me bucko, especially considerin' this doesn't come with any decals--checkerboard black/white pattern on t' fins, me hearties, me hearties, and vertical stripes. T' Semroc cover art looked a little nicer and easier, arrr, so I tried t' follow their lead a bit. Aye aye! I started with a gray primer base, then followed by paintin' the body tube and fins a dark red metallic. Ahoy! Avast, me proud beauty! T' nose cone was painted with a gold metallic left over from me Sky o' Gold spree.

T' Semroc cover art also included a neat lookin' set o' black trim stripes--one vertical stripe with horizontal bands at each end. Ahoy! Ahoy! Blimey! Havin' just masked and painted a couple Saturn 1b's, me bucko, me bucko, I felt up t' t' challenge and so cut some rectangular bands o' tape about 2-3/8" long, then drew a vertical line up t' body tube (from forward fin joint) usin' a short piece o' angle. That line would represent me centerline for t' vertical black band. Begad! I then applied the 2-3/8" strips o' tape about 3/8" short o' each end o' t' line, with t' gap (2-3/8" is too short to make it around t' body tube) centered over t' line. Begad! I then masked off horizontal bands for t' other end o' the 3/8" top/bottom bands, and shot t' exposed areas with Rustoleum® gloss black.

T' finished effect doesn't look quite as nice as t' Semroc cover art, matey, but I was fairly pleased. Aye aye! I'd like t' have gone a lighter red, but t' metallic is a nice effect.

Construction Rating: 4 out o' 5

Flight:
Recommended motors are all long delay 18mm's o' A8-5, me hearties, me hearties, B6-6, ya bilge rat, me bucko, arrr, C6-7. Begad! I grabbed an A8-3 from an open Blast Off Flight Pack I'd picked up for half price. Avast! Ya scallywag! It absolutely boogied off t' pad and even on an A8 be a strain t' track t' apogee. T' delay was very clearly too early and even a -5 would be slightly before apogee. Begad! I suspect I could also track this on a B, but unless you're feelin' lucky avoid usin' C's unless usin' some trackin' powder as truely out o' sight flights would be in order.

Recovery:
T' tiny (8") crepe paper streamer is mainly decorative/complyin' with safety code and does nay really affect the descent rate. Avast! Begad! T' model is small and light enough nay t' care. Despite upgradin' t' Keelhaul®©™®/elastc shock cord, I still managed t' suffer a smiley dent in t' nose cone. Avast, me proud beauty! Guess I should have gone with even more elastic.

Flight Rating: 4 out o' 5

Summary:
While thar's nothin' all that strikin' about this design (other than t' fact it's less ugly than t' Mark II), it is a nice simple construction, uses quality components and thar's clearly a nostalgic retro aspect t' it. Blimey! It flies great. Arrr! T' only cons I'd offer are related t' t' adherence t' t' original design--rubber shock cord/tri-fold mount and a decal for stripe t' match t' cover art would be sweet (though certainly add a buck or two t' t' cost).

Overall Rating: 4 out o' 5

Other Reviews
  • Semroc Mark By John Thompson (October 16, 2008)

    Brief: I received this kit from Semroc at NARAM 50. Semroc gave the Mark to anyone who purchased a kit from them. The Mark is a reproduction of the Estes kit #K-02 and is part of the Semroc XKits line. The XKits line of rockets are beautifully recreated reproductions of classic Estes, FSI, and Centuri rockets we remember as kids. The Mark is a simple, super light 3FNC rocket ...

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